Basalt is the most common constituent of the earth’s crust and is found in two main derivatives of cooled magma − columnar (such as the Giants Causeway) or lava plateaus. The material has very little grain due to its original low viscosity when in its molten state.
Occasionally, zeolites and silicas may be combined within the Basalt. Basalt is hard and virtually non porous.
Basalt’s extremely dense surface and hardness made it a favourite stone for cobbles and setts where iron shod horses and iron wheeled carts would be constantly in use; so one finds it as an historic material in docks, coal mines, shipyards and the streets of mercantile cities. It is usually only available in small plan sizes which limits its appeal for some design applications.
|Stone Type Code||Stone||Colour||Available Finishes|
|B||Leipzig||Grey/Black||RA, RS, DS, P, FP, FF, A|
Small pavers, setts, cubes, cobbles, small masonry blocks.
|DS||Diamond Sawn||F||Flamed||FP||Fine picked||RA||Riven, all faces|
|SB||Sandblasted||FF||Fair picked||RS||Riven and sawn edges||A||Axed|